Vehicles are recently required to reduce noises in their compartments from engines, and switches for switching of windshield wipers and fog lamps are accordingly required to reduce noises generated from the switches.
FIG. 4 is a cross-sectional view of conventional swing-action type rocker switch 101. FIG. 5 is an exploded perspective view of rocker switch 101. A top surface of operating button 2 protrudes from an upper opening of upper cover 1. Operating button 2 fits in an upper protrusion of drive member 3. Shafts 3A and 3B provided substantially at a center of drive member 3 projects to function as fulcrums and are inserted in supporters 4A and 4B of case 4, respectively. Wiring board 5 has wiring patterns (not shown) formed on top and rear surfaces of the board. The rear surface of wiring board 5 contacts a top surface of lower cover 6. Auxiliary switches 7 and 8 are spaced from each other on the top surface of wiring board 5, and the fulcrums are positioned between auxiliary switch 7 and auxiliary switch 8. Auxiliary switches 7 and 8 have a push-shaft 7A and 8A, respectively. The switches 7 and 8 are self-resetting type switches operable to be turned on when push-shafts 7A and 8A are pushed and to be turned off when the shafts are released. Top surfaces of push-shafts 7A and 8A protrude from openings of case 4 and face push-sections 3C and 3D on the rear surface of drive member 3, respectively. Stoppers 3E and 3F having substantially spherical shapes are located outward from push-sections 3C and 3D and face contact sections 4E and 4F on the top surface of case 4, respectively. Coil spring 9 is accommodated in tubular section 3G projecting out downward substantially from the center of drive member 3. Pin 10 is provided on the bottom end of tubular section 3G. Spring 9, being slightly bent, urges pin 10 toward recess 6A provided unitarily with the bottom section of lower cover 6. A bottom of lower cover 6 has recesses 6B and 6C provided at respective ones of both sides of recess 6A. Spring 9 urges and presses pin 10 against recess 6A, and have drive member 3 located at a neutral position, as shown in FIG. 4. Output terminals 7B and 8B of auxiliary switches 7 and 8 are electrically connected to an electronic circuit (not shown) of the vehicle through connector 5A of wiring board 5.
FIG. 6 is a cross-sectional view of rocker switch 101. When the top surface of operating button 2 is pushed in direction F1, tubular section 3G of drive member 3 swings to a left position of the fulcrum from the neutral position, and pin 10 moves to left from recess 6A. Then, pin 10 moves to recess 6B through passing over protrusion 6D provided between recess 6A and recess 6B. Swinging motion of tubular section 3G stops when stopper 3F on the rear surface of drive member 3 contacts contact section 4F on the top surface of case 4, and a collision noise is generated. Simultaneously, push-section 3D on the rear surface of the drive member pushes push-shaft 8A of auxiliary switch 8, thus turning on auxiliary switch 8. The electronic circuit of the vehicle detects though a signal via terminal 8B and connector 5A that auxiliary switch 8 is turned on, and, for example, causes a wiper to operate intermittently.
Similarly to above, when an upper-left surface of operating button 2 is pushed, tubular section 3G of drive member 3 swings from the neutral position to a right position about the fulcrum, and pin 10 on recess 6A moves to right. Then, pin 10 moves to recess 6C through passing over protrusion 6E provided between recess 6A and recess 6C. The swinging of the tubular section stops when stopper 3E on the rear surface of drive member 3 contacts contact section 4E on the top surface of case 4, and a collision noise is generated. Simultaneously, auxiliary switch 7 is turned on and the electronic circuit of the vehicle detects through a signal provided via terminal 8B and connector 5A that auxiliary switch 7 is turned on, and, for example, causes the wiper to operate continuously.
In order that drive member 3 can keep the neutral position, the left position, and the right position even with shocks and vibrations during driving of the vehicle, spring 9 necessarily has a large urging force.
In conventional rocker switch 101, the large urging force of spring 9 allows stoppers 3E and 3F of drive member 3 to contact sections 4E and 4F with a large force when switching, thus generating a large collision noise.